Liquid fuel pumping apparatus for supplying fuel to internal combustion engines



April 14, 1970 K. A. w. KEMP 3,506,381

LIQUID FUEL PUMPING APPARATUS FOR SUPPLYING FUEL To INTERNAL" COMBUSTION ENGINES 2 Sheets-Sheet 1 Filed May 20, 1968 ATTORNEY 3,506,381 UEL TO April 14, 1970 LIQUID Jaw/ 520 United States Patent 3,506,381 LIQUID FUEL PUMPING APPARATUS FOR SUPPLYING FUEL T0 INTERNAL COMBUS- TION ENGINES Kenneth Albert Walters Kemp, Ealing, London, England, assignor to C.A.V. Limited, London, England Filed May 20, 1968, Ser. No. 730,362 Claims priority, application Great Britain, May 23, 1967, 23,884/ 67 Int. Cl. F04b 13/00, 1/00; F02m 39/00 US. Cl. 417485 1 Claim ABSTRACT OF THE DISCLOSURE A fuel pumping apparatus for supplying liquid fuel to a six cylinder internal combustion engine and comprising three pumping plungers located within respective bores formed in a rotary distributor member and a cam ring surrounding the distributor member, the cam ring having two sets of cam lobes each set comprising three lobes which are equi-angularly spaced about the axis of rotation of the distributor, the two sets of cam lobes being angularly spaced so that successive injections strokes of the pumping apparatus occur at the desired intervals.

This invention relates to liquid fuel pumping apparatus for supplying fuel to a six cylinder internal combustion engine, and of the kind comprising an injection pump adapted to be driven in timed relationship with the engine with which the apparatus is associated and a rotary distributor for distributing fuel pumped by the injection pump during successive injection strokes to each in turn of six outlet ports.

The object of the invention is to provide such an apparatus in a simple and convenient form.

According to the invention in an apparatus of the kind specified the injection pump comprises three pumping plungers located within respective bores formed in the distributor member and equi-angularly spaced about the axis of rotation thereof, and a cam ring mounted about the axis of rotation of the distributor, the cam ring having two sets of cam lobes each set comprising three lobes which are equi-angularly spaced about said axis, the cam lobes acting to impart inward movement to the pumping plungers as the distributor rotates, the two sets of lobes being angularly spaced so that successive injection strokes of the injection pump occur at the desired intervals.

In the accompanying drawings:

FIGURE 1 is a sectional side elevation of one example of an apparatus in accordance with the invention;

FIGURE 2 is a section on the line 2-2 of FIGURE 1.

The liquid fuel pumping apparatus shown in the drawing is for supplying fuel to a six cylinder compression ignition engine of the V-type. The angle between the two banks of cylinders of the engine being 90. The particular engine requires fuel to be supplied to it at unequal intervals of pump rotation of 45, 75, 45, 75, etc. It will be appreciated however that the apparatus is equally able to supply fuel to engines having 60 or 120 V angles and to a conventional six cylinder engine having its cylinders in line.

The apparatus comprises a body part in which is mounted a rotary cylindrical distributor 11 which is adapted to be driven in timed relationship with the engine with which the apparatus is associated. At one end of the distributor is formed three radially extending equi-angularly spaced bores 12 which accommodate pumping plungers 50 respectively. Bearing against the outer ends of the pumping plungers are shoe pieces respectively each of which mounts a roller 52, which co-operates to effect inward movement of the associated pumping plungers, with cam lobes formed on the internal periphery of an annular cam ring 51 which surrounds the distributor at this point. The cam ring, see FIGURE 2, is formed with two sets of lobes 53, 54 and each set comprises three lobes which are equi-angularly spaced relative to each other about the axis of rotation of the distributor. Moreover, the two sets of cam lobes are angularly spaced from each other by 45. The effect of this spacing is that all three pumping plungers 50 are moved inwardly simultaneously to inject fuel at 45, 45 etc. intervals ofl pump rotation.

The inner ends of the bores which accommodate the pumping plungers are in communication with each other and also with a longitudinal passage 15 formed in the dis tributor. The end of the passage remote from the pumping plungers is closed by a plug member 16 which also constitutes an abutment for a coiled compression spring 21 the purpose of which will be described later in this specification. Adjacent the plug member there is in communication with the longitudinal passage, a radially disposed delivery passage 17 and this is arranged to register in turn and as the distributor rotates, with six outlet ports 18 which are formed in the body part. The circumferential spacing of the outlet ports corresponds with the spacing of the cam lobes and the delivery passage is arranged to register with an outlet port during the time when the pumping plungers 50 are being moved inwardly by the cam lobes. In use, the outlet ports are connected to the fuel injection nozzles (not shown) of the associated englue.

The longitudinal passage 15 intermediate its ends defines a cylinder in which is mounted a movable shuttle 19. Moreover, at opposite ends of the cylinder the longitudinal passage is in communication respectively with two sets of inlet passages 22, 23. The two sets of inlet passages are arranged to register in turn and as the distributor rotates with two sets of inlet ports 24, 25 formed in the body part. This registration takes place whilst the plungers 50 are permitted to move outwardly by the cam lobes.. The two sets of inlet ports communicate with a fuel proportioning device which is capable of proportioning .the amount of fuel which flows from a source of fuel under pressure, to the opposite ends of the cylinder. The total quantity of fuel which flows through the two sets of inlet ports is constant however, and by adjustment of the fuel proportioning device the relative amounts of fuel which flow to the opposite ends of the cylinder can be adjusted.

The source of fuel under pressure mentioned above comprises a vane type feed pump 13, the rotary part of which is mounted upon the end of the distributor remote from the pumping plungers. The stationary part of the feed pump is secured within the body part and is provided with an inlet and an outlet port. The outlet port is in communication with a passage 14 formed in the body part and this passage conveys fuel to the fuel proportioning device. The inlet port of the feed pump in use, is connected to a source of liquid fuel and the inlet and outlet ports are interconnected by a control valve (not shown) whereby the outlet pressure of the feed pump is made to vary in accordance with the speed at which the distributor rotates.

The fuel proportioning device takes the form of an angularly adjustable cylindrical member 55 mounted within a complementary cylinder 26 formed in the body part. The cylindrical member is provided with a pair of diametrically disposed grooves which register respectively with ports formed in the wall of the cylinder. These ports are in communication respectively with the sets of inlet ports 24 and 25 previously mentioned. The angular setting of the member is determined by a speed sensitive governor (not shown) the datum setting of which is under the control of the engine operator.

The longitudinal passage intermediate the aforesaid cylinder defined therein and the plug is of enlarged diameter so that a step is defined at the end of the cylinder nearest the plug. Moreover, mounted within this portion of the passage is a plate valve which is urged into contact with the step by means of the aforesaid coiled compression spring 21. The shuttle at its adjacent end is provided with an extension of reduced diameter for cooperation with the plate valve as will be described. Moreover, the extent of movement of the plate valve against the action of its spring is limited by an abutment extending from the plug.

In use, at the end of the inward movement of the pumping plungers 50 when delivery of fuel through the delivery passage 17 to an outlet port -18 has ceased, further rotation of the distributor member permits the plungers to move outwardly and the coiled compression spring 21 moves the plate valve 20 together with the shuttle 19 in a direction towards the plungers. The effect of this is to permit some of the fuel which previously flowed through the outlet port to flow back into the longitudinal passage 15. This reverse flow continues until the plate valve contacts the step. Moreover, the movement of the shuttle displaces fuel into the bores 12 which accommodate the pumping plungers. Upon further rotation of the distributor member the delivery passage 17 is moved out of. register with the outlet port 18 and the two sets of inlet passages 22, 23 are brought into register with the two sets of inlet ports 24, 25 respectively. Fuel now flows into the opposite ends of the cylinder and the shuttle 19 moves towards the bores 12. As has previously been mentioned the total volume of fuel which flows into the longitudinal passage remains constant but the proportion of fuel fed to the opposite ends of the cylinder is varied so that the shuttle at the end of the filling stroke, occupies a position nearer to the bores which accommodate the pumping plungers, the position being determined by the setting of the fuel proportioning device.

During further rotation of the distributor member the registration of the sets of inlet passages 22, 23 with the sets of inlet ports 24, 25 is broken and the delivery passage is brought into register with the next outlet port. Further rotation of the distributor member causes inward movement of the pumping plungers 50 and fuel is delivered to the longitudinal passage .15 and acts upon one end of the shuttle 19 to cause axial movement thereof. Fuel is displaced by the opposite end of the shuttle and this flows through the delivery passage and outlet port to the associated engine. During this process the plate valve 20 is liftedslightly by the flow of fuel from the step in the longitudinal passage and against the action of the coiled compression spring. Towards the end of the movement of the shuttle the extension thereof contacts the plate valve Which is then moved a further amount against the action of the coiled compression spring 21. At

a predetermined position the shuttle uncovers a spill passage which communicates with the cylinder intermediate the ends thereof, the spill passage being brought into register at the appropriate time with one spill port 31 of a set of spill ports formed in the body part. As soon as the shuttle opens the spill passage, excess fuel escapes from the longitudinal bore and movement of the shuttle 7 ceases so that injection of fuel to the engine also ceases.

' as an unloading delivery valve to control the residual pressure in the outlet ports at the end of the injection stroke, individual delivery valves may be provided in the outlet ports respectively.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

v 1. A liquid fuel pumping apparatus for supplying fuel to a six cylinder internal combustion engine of the V type and comprising in combination, an injection pump adapted to be driven in timed relationship with the engine with which the apparatus is associated and a rotary distributor for delivering fuel pumped by the injection pump during successive injection strokes to each in turn of six outlet ports, the injection pump comprising three pumping plungers located and slidable within respective bores formed in the distributor member and equiangularly spaced about the axis of rotation thereof, and a cam ring mounted about the axis of rotation of the distributor, two sets of cam lobes comprising three lobes which are equiangularly spaced about said axis, the cam lobes acting to impart inward movement to the pumping plungers as the distributor rotates, the two sets of cam lobes being angularly spaced with respect to each other so that successive injection strokes of the injection pump occur at the desired intervals and the individual crests of each cam lobe have uneven angular spacing.

References Cited UNITED STATES PATENTS 2,819,677 1/1958 Leath l03161 X 2,901,974 9/1959 Evans 103-161 X 3,267,861 8/1966 Pigeroulet et al.

3,319,616 5/1967 Glikin 123-139 DONLEY I; STOCKING, Primary Examiner W. I. KRAUSS, Assistant Examiner U.S. Cl. X.R. 

